ASK TOM WHY.

Dear Tom, In the last 20 years, how many days per...

September 10, 2002|By Tom Skilling, chief meteorologist at WGN-TV.

Dear Tom,

In the last 20 years, how many days per year on average does Chicago reach 100(degrees)?

Tanya

Dear Tanya, One-hundred degree days are a relatively rare event in Chicago, having occurred at the official observation site on only 60 days since weather records began in 1872. In fact, Chicago has not experienced a 100 day since July 30, 1999, when the thermometer at O'Hare Airport topped out at 101(degrees).

According to Chicago climatologist and weather historian Frank Wachowski, since 1983 the city has sweltered through 15 days where the official temperature reached at least 100(degrees)--an average of less than one per year. However, that number is severely impacted by the torrid drought summer of 1988, when Chicago recorded seven days of triple-digit heat.

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Tom Skilling is chief meteorologist at WGN-TV. His forecasts can be seen Monday through Friday on WGN News at noon and 9 p.m.